which is better for New emaxx? 1 motor or 2?

[raptor50]

Im thinking of getting the e maxx but going straight w/ BL pwr. I have mamba max 5700 lying around along with Nemesis 7XL. Should I get another mamba max 5700 and make it 2 BL pwr with 6S config. or should I get another mamba max ESC only, and make it single motor w/ 7xl and go 4S? kinda confused.

also, is converting to twin pwr. pretty easy or is it complicated? thanks..